Question

f a number n is subtracted from 18, the result is four less than n. What is the value of n?

Answer 1

18 - n = n - 4
18 + 4 = n + n
22 = 2n
22/2 = n
11 = n <==

Answer 2

you could use the equation 18-n=n-4 to figure out that n equals 11